Oyster culture basket

ABSTRACT

A basket suitable for culturing of oysters, the basket being particularly adapted to be supported above a sea bed. The basket is formed of plastics material by injection moulding, and has a central hole which may be fitted around a pole or standpipe. The basket includes a bottom, an outer wall, and an inner wall surrounding the central hole in the bottom, and the basket also includes partitions extending across the annular area between the outer and inner walls. The baskets are stackable, and a number of the stacked baskets forms a suitable unit for handling. A process for purification of oysters using the baskets is also described.

1451 Mar. 11, 1975 Woodridgc et a1.

1 1 OYSTER CULTURE BASKET Hero1zer.............. 3 727,579 4/1973 3 741,159 6/1973 Halaunbrenner....l,................v

Inventor: Douglas McNicol, R.R. No. 2, River Denys, Nova Scotia, Canada or FirmSpencer & Kaye Primary Examinerl-1ugh R. Chamblee Attorney, Agent 3 7 9 l n. 6 m5 3 m N .ml 0. MP FA NH 22 [57] ABSTRACT A basket suitable for culturing of oysters, the basket March 30 Related US. Application Data [63] Continuation-impart of Ser. No. 129,547

1971, abandoned.

being particularly adapted to be supported above a sea [30] Foreign Application Priority Data bed. The basket is formed of plastics material by injection moulding, and has a central hole which may be fitted around a pole or standpipe. The basket includes a bottom, an outer wall, and an inner wall surrounding the central hole in the bottom, and the basket also includes partitions extending across the annular area be 7 403 W Wm M 11 l M m WW WM1 a mmm d a a n u a C U 1 N 7 u" w S I n hf 0 G 0 d b Ld e n. F UIF 1 M 555 1.1.1

tween the outer and inner walls. The baskets are stackable, and a number of the stacked baskets forms a suitable unit for handling. A process for purification of oysters using the baskets is also described.

[56] References Cited UNITED STATES PATENTS 17 Claims, 9 Drawing Figures 24 99 11 mm t e 5 MC u SL 75 56 99 11 87 59 49 000 42 09 7-3 PATENTEI] MARI I [975 SHEET 2 UF 5 PATENTEB MARI 1 1975 sum 5 o 5 I: -A 1 I m 0E m m 8N NW1 i 5 F8 J mom m: V as: mi 25 \HWNQ mi m dwm as? m as: n ti .1! |qm m3 OYSTER CULTURE BASKET This application is a continuation-in-part of my U.S. Pat. application Ser. No. 129,547 filed Mar. 30th 1971, now abandoned.

The present invention relates to a basket primarily intended for culturing of oysters, but also useful for culturing other shellfish. Also, the basket is useful in other processes involving shellfish; for example the purification of shellfish taken from contaminated water.

It is known that there are advantages in growing, or culturing, oysters while they are raised off the sea bed. The young oysters (or seed oysters) are placed in haskets, which are raised off the sea bed for example by being suspended from rafts. Oysters grown in this way grow faster and become fatter than oysters growing naturally on the sea bed, due to the better circulation of water around them. Also, the oysters are protected from their natural enemies, such as starfish, which usually crawl on the sea bed.

Hitherto, baskets used for oysters have generally been in the form of flat rectangular trays. These trays have various drawbacks. If the trays are made large enough to be stable the oysters sometimes pile up on one side or the other and do not grow well. The oysters also tend to grow together and not as many well shaped oysters are produced. Also, the larger the tray the more difficult it becomes for oysters in the centre of the tray to get their share of water, in other words circulation is a problem. In addition, handling of large trays is difficult. Also, the materials used in the past to construct such trays have been unsatisfactory. Wood, unless it is treated chemically every year, is attacked by boring organisms and deteriorates quite quickly. Metal is heavy and expensive. Screening materials are expensive and in some cases need treatment to prevent rapid weakening. Materials reinforced with glass fibre show promise but have so far been too expensive. The fabrication of trays from these materials is mostly by hand production, and this again is expensive.

It has been proposed according to French Pat. of Addition No. 94,530 to Foucault to make an oyster culture basket from a plastics material, and to provide means for locating the oysters in place. While this material and method of construction is generally good, the actual design would seemingly be expensive to manufacture, and the circulation of water through the oysters would still be a problem. In fact Foucault suggests a wide spacing between baskets to allow for sufficient circulation at the centre of the basket. Although a small aperture is provided in the bottom of this basket this is too small, and the entry thereinto too restricted, to contribute substantially to circulation.

The basket of this invention gives various advantages over the known baskets, including good circulation (even with small spacing between adjacent baskets), ease of connecting a plurality of the baskets into a stack, and suitability for use in a purification process to be described.

The basket of this invention has a bottom,an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being perforated to allow for circulation of water. The basket further includes at least three dividers extending between the said inner and outer walls, said dividers dividing the basket into at least-three segments surrounding said hole, each segment occupying less than the full width of the basket.

The basket is preferably circular with a central hole, the hole being at least one eighth the diameter of the basket, although the hole is preferably much larger than this, say at least one sixth or at least one quarter the diameter of the basket. At least some of the dividers are preferably in the form of removable partitions having their bottom edges located in grooves in the bottom of the basket, and having their vertical edges locatablc by vertically extending locating means in the inner and outer walls. The vertically extending locating means may be grooves or slots, or like recesses, between vertical ribs or pillars in the inner and outer walls.

In the basket of this invention, good circulation is assured by the presence of a central hole, the inner wall surrounding this hole being perforated or of lattice type construction. This good circulation increases the feeding rate and therefore the rate of growth of the oysters. Increased circulation also increases the rate of removal of waste materials from the oysters, which also helps the growing process and reduces the possible spread of disease. The central hole also allows the baskets to be stacked on a standpipe with the holes surrounding the standpipe so that water can flow from ports in the walls of the standpipe and then radially through the inner and outer walls of the basket.

The use of dividers prevents the oysters from piling up on one side of the basket. The use of dividers allows oysters to be separated for example so that they can be individually identified. However, in quiet waters, the dividers may be removed to improve circulation of water.

The bottoms and side walls of the basket are preferably integrally formed of plastics material by injection moulding, and are all preferably of lattice construction. The dividers may also be of lattice construction.

Another feature of preferred embodiments of this invention is that the baskets are made to be stackable, i.e., the baskets each include means suitable for registering with and locating the bottom of an identical container. In the preferred construction, at least some of the dividers are integrally moulded with the said bottom and said walls, and the dividers include vertically aligned registering means formed in the tops and bottoms of said dividers, said registering means including spigots and recesses which spigots are engageable in the recesses of an identical basket whereby the baskets are stackable.

The invention also comprises a process for purification of shellfish, comprising the steps of:

supporting contaminated shellfish on the bottoms of baskets and confining said shellfish in an annular space between perforated inner and outer walls of said baskets,

placing a stack of said baskets on a vertical standpipe projecting upwardly from the bottom of a tank holding water in which said baskets are submerged, said baskets being located with their inner walls surrounding said standpipe, and

causing relatively pure water to pass through said standpipe and out of ports spaced along said standpipe, said water being supplied at pressure sufficient to flow outwardly from the ports and radially through the baskets against the pressure of the surrounding water.

bodiment of basket,

FIG. 2 is a plan view of a portion of the basket of FIG. 1 with one partition removed, a

FIG. 3 is a cross-section through the outer wall of the basket with the partitions removed, on line 33 of FIG. 2, I

FIG. 4 is a side elevation of a removable partition used in the basket, l

FIG. 5 is a perspective view of a portion of the inside of the outer wall of the basket, from which a partition has been removed,

FIG. 6 is a view of a number of the baskets of FIG. 1, shown stacked and partially in section,

FIG. 7 is a plan view of a modified basket,

FIG. 8 is a view on section line 88 of FIG. 7, and also shows in broken lines a second basket stacked on top of this basket, and

FIG. 9 shows a partially sectioned elevation of a stack of the modified baskets used as part of a shellfish purification apparatus. v

Referring to FIGS. .1 to 6 of the drawings, the basket is circular, having a circular bottom 10 ofabout 18 inches in diameter surrounded by an upstanding outer wall 11 which is about 2 inches in height. The bottom 10 has a central circular hole of about 6 inches in diameter, which is surrounded by an upstanding inner wall 12, the inner and outer walls being of substantially the same height.

The bottom 10, and the inner and outer walls 11 and 12, are all formed integrally of plastics material by injection moulding, and are all of lattice type construction as shown in FIGS. land 2. As shown in FIG. 2, the bottom comprises a series of concentric rings, joined by radial ribs. The outer and inner concentric rings 14 and 15 respectively are reinforced, and there are also provided twelve equispaced ribs 16 which are wider than the remainder. The outer and inner walls 11 and 12 extend upwardly from the outer and inner rings 14 and 15 of the bottom. The outer wall includes a series of pillars 17 extending upwardly from the bottom ring 14, and carrying at their upper ends a top outer ring 18.. The lower ends of pillars 17 each coincide with the outer endof a radial rib. The side wall area between the rings 14 and 18 is provided with circular horizontal rings 19 which form a lattice with pillars 17. The inner wall 12 is similarly constructed, having vertical pillars 21 carrying a top inner ring 22, the area between these pillars andthe top and bottom rings being provided with horizontal rings to form a lattice. Asshown in FIG. 3, the top outer ring 18 extends outwardly beyond the main part of the outer wall 11. The bottom outer ring 14 is provided with small outwards facing rebate.

The wide ribs 16 of the bottom are raised above the level of the other ribs, and are each provided with a central longitudinal groove 24, which serves to locate thebottom edge of a partition 28 (also shown in FIG. 4). Also, associated with the outer end of each rib 16 are two closely spaced pillars l7',and associated with the inner end of the rib 16 are two similarly spaced pillars 21'. These pairs of closely spaced pillars provide vertically extending recesses in the form of slots which locate the vertical edges of the partitions 28. FIG. 5 shows a perspective view of the outer end of a grooved rib 16, with an associated part of the outer wall.

All the parts of the basket so far described, with the exception of the partitions 28, are integrally produced from plastics material (preferably polyethylene or polypropylene) by injection moulding. The partitions themselves, which are shown in detail in FIG. 4, are also separately produced by injection moulding, and are of similar construction as the remainder of the basket, having a rectangular lattice surrounded by a somewhat reinforced. perimeter. The lower edge of each partition is engageable in the groove 24 of a rib 16. In addition, the vertical edgesof the partitions each have three lugs 29 which are engageable between the closely spaced pillars l7 and 21" of the outer and inner walls. The partitions are inserted in place by bending the outer wall outwards and the inner wall inwards, and then inserting the partition with its lower edge in groove 24, allowing the walls to snap back into position holding the lugs 29 between the closely spaced pillars 17' and 21 The partitions are substantially the same height as the inner and outer walls.

The bottom of the basket has three posts 32 integrally moulded threwith, and extending upwardly to just above the height of the top outer ring 18. The upper ends of these posts are engageable in registering holes 35 moulded in the bottom of an identical basket when such baskets are stacked (see FIG. 6). The positions of posts 32 are shown in FIG. 2. The engagement of the posts 32 in the holes 35, as seen in FIG. 6, ensures good positive location of the baskets when stacked. Also, the posts 32 are arranged so that when baskets are stacked together there is a small gap between the top of ring 18 of one basket and the bottom of the next basket, so that substantially all the weight of a stack of baskets is transmitted through the posts. This feature minimizes the distortion of baskets when they are loaded and stacked. Also, the posts 32 have axial bores, indicated at 34, and when the trays are stacked these bores are aligned and provide vertically extending guide means for locating vertical suspension rope means which may be inserted through the aligned bores to hold a stack of baskets together and to suspend the stack.

A top cover, for the uppermost basket of a stack, may be necessary where the water is rough or where the method of handling may cause spillage from the top basket. The preferred form of cover is a simple solid disc, fitting within the top outer ring 18.

The basket as described is light in construction, not liable to corrosion, and convenient to use. The use of a central hole, surrounded by the inner wall which is of lattice construction, along with the use of lattice construction for the bottom and the outer wall andthe partitions, ensures good circulation. The stackable feature of the trays is obviously advantageous, both in setting up trays in their position, raised off the sea bed, and in handling of the trays, since a number of the trays can be held together in the form of a convenient package, which may be handled easily by one man without mechanical assistance. A stack of trays holds a large number of shellfish in a small space. The stack of trays allows the grower to move his shellfish inexpensively from one area to another; to move the shellfish to less saline waters for disease control and fouling control; to move the shellfish to more saline waters to improve saltiness and flavour; and to move the shellfish to waters where they can fatten or grow more quickly. The grower can thus manage his shellfish without the expense (and losses) that go along with harvesting and reharvesting.

The stacked trays may be supported off the bottom of the sea bed in various ways. Firstly, the stackmay be suspended from rafts or individual floats. Also, the baskets can be hungfrom fences erected of poles, or hung from long lines, which are lines strung from one float to another. Also, a stack of baskets can be supported on individual stakes in shallow water, the stake going through the centre hole of the baskets. Also, a stack of baskets can be placed on a stand with legs by which it is raised off the bottom, and yet well beneath the surface. This latter method also has the advantage of keeping the baskets out of the way of other users, for example boaters, fishers, or water skiers, and also avoids any difficulties caused by ice.

The stackability of the baskets is also useful, in that a package of the stacked baskets can be easily cleaned by water jets, or by dipping in a bath of brine to destroy fouling organisms, or possibly in chemical dips such as copper sulphate.

FIGS. 7 and 8 illustrate a modified and preferred form of basket.

The modified basket is generally similar to that of FIGS. 1 to 6, being generally circular in plan view, with a generally circular bottom 110 surrounded by an upstanding outer wall 111, and having a central hole of about one third the diameter of the outer wall which hole is surrounded by inner wall 112. Inner and outer walls 112 and 111 are of substantially the same height, and these walls as well as bottom 110 are integrally moulded of plastics material and are of lattice construction. The walls have a height of about 2 inches, and the central hole is about 6 inches in diameter.

The basket also includes, as does the first embodiment, means for locating removable partitions; for simplicity, only these locating means, and not the partitions themselves, are shown in the drawings. The partitions used are however identical to that shown in FIG. 4. The locating means include wide, radial bottom ribs 116 provided with longitudinal grooves 124, and slots in the inner and outer walls provided by closely spaced pairs of the pillars forming these walls, all exactly as described for the first embodiment. In this second embodiment, however, there are provided means for locating only nine such partitions instead of twelve as with the first embodiment. In addition there are provided three fixed dividers 140, equispaced around the basket, and dividing the basket into three equal segments which are each capable of being divided into four small segments by the removable dividers.

The fixed dividers 140 are integrally moulded with the bottom and walls of the basket; these are unperforated however for ease of moulding. The outer portions of dividers 140 are bifurcated to form two side portions 140a spreading outwardly from the solid inner portion 140b, and curving away from each other near the perimeter of the basket to merge with outer wall 111. The side portions 140a of the dividers thus constitute the sides of vertical grooves indicated at A extending radially of the basket, these grooves being open top and bottom and extending through the outer wall 111. The outer wall is thus discontinuous, although being generally circular. The grooves A provide guide means for locating vertical ropes connecting together a stack of the baskets.

The solid inner portion of the dividers has a horizontal base extension 142 bridging the inner ends of portions 140a, and having its extremity provided with a post 132 extending upwardly therefrom to a height just above that of the outer wall. The upper end of post 132 has a spigot 132a, and the base extension 142 has a correspondingly situated recess 135 co-axial with the post, the spigots and recesses being spaced inwardly of the bases of grooves A, so that when two or more baskets are stacked as in FIG. 8 the spigots of one basket can locate in recesses 135 of an identical basket.

The extensions 142 each have a vertical bore 144, spaced inwardly from post 132, the purpose of which is to provide fixing means for the end of ropes used to hold a stack of the baskets together. For this purpose, before a stack of baskets is assembled, a rope 145 is inserted through each of the bores 144, the rope being knotted at its upper end and pulled through until the knot 146 rests on top of the extension 142. After assembly of a stack of the baskets, with spigots 132a registered withappropriate recesses 135, the ropes 145 are pulled upwardly around the baskets and into grooves A, and are then secured together above and close to the centre of the top basket. The ropes may be secured together by thrusting a nail through the lay of the three ropes, or by a special fastening device. The roped together stack is illustrated in FIG. 9. By the use of grooves A in accordance with this embodiment the time taken to rope together a stack of baskets is much reduced as compared to the time required for passing ropes through the bores 34 of posts 32 of the first embodiment.

Solid, unperforated, dividers are used in this embodiment because they can be moulded more easily than perforated dividers. However, such dividers do reduce circulation, and this effect may be counteracted by making the dividers less than the full height of the basket.

FIG. 9 shows apparatus for purification of shellfish taken from contaminated waters.

Nowadays, many otherwise good shellfish growing areas of the sea are polluted. These polluted areas are still attractive to shellfish growers because of convenient location and because the waters have plenty of food. It has beem found that oysters and other shellfish takenfrom such areas can be rendered suitable for consumption by a purification process, or so-called depuration" process, in which the shellfish are harvested and placed in tanks of water provided with means for purifying the water in the tank and for passing the puritied water over the shellfish.

FIG. 9 shows the use of the baskets of this invention in the depuration process. The drawing indicates a portion of a tank holding water 200, the tank having a bottom 201. Along the tank bottom extends a manifold pipe 203, from the upper side of which extend upwardly a series of standpipes of about 2 inches diameter, one of which is shown at 205. The standpipe has numerous ports 207 in its side wall, and terminates in a free upper end suitable for removably receiving a shell fish basket having a hole locatable on the standpipe, and this upper end is capped at the top by a closure 208. Located on the standpipe is a stack of the baskets as previously described with reference to FIGS. 7 and 8, roped together by rope means 145, the inner walls 112 of each basket surrounding the standpipe. Supported on the bottoms of the baskets, and confined in the annular space between the inner and outer walls of the baskets, are contaminated oysters 210, which oysters may have also been grown in the same basket. The level of water 200 in the tank is sufficient to submergeall of the baskets. Pumping means are provided for causing relatively pure water (i.e., pure relative to the water of the growing area) to flow through the manifold pipe 203, upwardly through the standpipes 205, and outwardly through ports 207 and radially through the baskets, the water being supplied at pressure sufficient to flow outwardly from the stand pipes against the pressure of the srrounding water. It has been found that, with suitable relatively pure water and flow rates, contaminated oysters can be rendered fit for human consumption, using this process, in between about 24 hours and 48 hours, depending on the species and the amount of pollution.

The relatively pure water supplied to manifold 203 is preferably purified and oxygenated water obtained by removing contaminated water 200 from the tank, adding oxygen, and irradiating with ultra-violet light to kill bacteria present. Food can be added to the water to fatten the oysters.

It will be apparent that the use of the stacked baskets, with their central holes surrounding the standpipes of the tanks, ensure evenness of distribution of water and any food carried thereby, to all of the oysters.

The basket in accordance with this invention may also be useful in the cultivation of other shellfish such as clams and scallops, and also possibly for crustacaea and for certain fishes.

Other uses of the basket described include:

1. Artificial feeding. Shellfish in poor condition can be placed in tanks and fattened by the addition of finely ground materials such as corn meal to the water. In such cases the baskets can be placed in tanks and standpipes used for supplying food enriched water, generally as in the purification process described above.

2. Many laboratories are keeping large numbers of shellfish in baskets for determining which individuals have the best characteristics for survival in conditions where there is a disease present, and also for work in genetics. It is normally necessary to mark each individual shellfish. However, by using these baskets and putting each shellfish in one compartment, and marking it on a card, the time consuming marking process is eliminated.

3. ln hatcheries. Where it is desired to keep large numbers of small shellfish in controlled conditions (heated, treated and filtered water) the need has been for trays which occupy a small space and yet allow good circulation. The basket of this invention will be very useful for this purpose.

The baskets described above are the preferred forms in accordance with the invention, but it will be understood that many variations of this form are possible which are within the scope of this invention. Thus, for example, in some instances baskets may be made and used without any dividers or partitions. As an alternative to the construction shown in FIGS. 7 and 8 with radial grooves extending through the outer wall of the basket, similar grooves could be provided extending through the inner wall. Connecting elements other than ropes may be used to securetogether a stack; the term rope means is intended to cover such other elements.

Also, instead of the partitions having their vertical edges locatable in slots between closely spaced pillars of the walls, these edges maybe located in grooves in the inner face of the outer wall and in the outer face of the inner wall.

I claim:

1. A basket suitable for the culturing of shellfish, and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wallof substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to allow for circulation of water, the basket further including at least three dividers extending between the said inner and outer walls, said dividers extending substantially the full height of the basket and dividing the basket into at least three segments surrounding said hole, each segment occupying less than the full width of the basket.

2. A basket according to claim 1, wherein said inner hole has a diameter at least twice as large as the height of said outer wall.

3. A basket according to claim 1 which is substantially circular, said hole being also circular and centrally located in the bottom and having a diameter at least one eighth the diameter of the basket.

4. A basket according to claim 1, wherein said bottom and said side walls are formed integrally of plastics material by injection moulding and are of lattice construction.

S. A basket according to claim 4, including integrally moulded means projecting upwardly above the level of the tops of said walls and shaped to engage correspondingly shaped integrally moulded registering means in the bottom of an identical basket, whereby the baskets are stackable.

6. A basket according to claim 5, having at least three integrally moulded, circumferentially spaced, and vertically extending guide means for locating vertical suspension rope means connecting a plurality of the baskets together into a stack.

7. A basket according to claim 1, wherein at least parts of said dividers constitute the sides of vertical grooves extending radially of said basket, said grooves being open top and bottom and extending through openings in said outer wall, whereby a plurality of said baskets may be fastened together by rope means fitted into said grooves by movement radially of the basket.

8. A basket suitable for the culturing of shellfish, and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to v allow for circulation of water, the basket further including means for locating removable dividers, said locating means comprising vertically extending recesses in the inner and outer walls.

9. A basket according to claim 8, wherein said inner hole has a diameter at least twice as large as the height of said outer wall.

10. A basket according to claim 8 which is substantially circular, said hole being also circular and centrally located in the bottom and having a diameter at least one eighth the diameter of the basket.

11. A basket according to claim 8, including inte- 12. A basket according to claim 11, having at least three integrally moulded circumferentially spaced, and vertically extending guide means for locating vertical suspension rope means connecting a plurality of the baskets together into a stack.

13. A basket suitable for the culturing of shellfish,

and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to allow for circulation of water, the basket further including integrally moulded means projecting upwardly above the level of the tops of said walls and shaped to engage correspondingly shaped integrally moulded registering means in the bottom of an identical basket, whereby the baskets are stackable.

14. A basket suitable for the culturing of oysters, having:

an apertured bottom with a hole of at least several inches in diameter,

an apertured upstanding outer wall surrounding said bottom and an apertured upstanding inner wall surrounding said hole,

a plurality of dividers extending between said inner and outer walls, said dividers being moulded integrally with the bottom and inner and outer walls,

at least parts of said dividers constituting the sides of vertical grooves extending radially of said basket, said grooves being open top and bottom and extending through openings in said outer wall, whereby a plurality of said baskets may be fastened together by rope means fitted into said grooves by movement radially of the basket, and wherein said dividers include integrally moulded spigots and recesses, the spigots and recesses being correspondingly placed and located adjacent opposite top and bottom sides of said basket, said spigots being locatable in the recesses of an identical basket whereby said baskets can be held together in register as a stack by said rope means.

15. A basket according to claim 14, wherein said spigots and recesses are spaced inwardly of the bases of said grooves.

16. Apparatus for feeding or purification of shellfish, by exposing the shellfish to food enriched or purified water, comprising:

a tank holding water,

a standpipe extending upwardly from the bottom of said tank, said standpipe having ports in its side walls and terminating in a free upper end suitable for removably receiving a shellfish basket having a hole locatable on said standpipe,

means for supplying food enriched or purified water to said standpipe at a pressure such that said water will flow out of said ports when the standpipe is submerged in water in the tank, and

a stack of baskets in accordance with claim 1 located on said standpipe each with its inner wall surrounding the standpipe said baskets being immersed in said water, whereby said enriched or purified water can pass from said standpipe radially through the baskets and over shellfish held therein.

17. A process for feeding or purification of shellfish,

comprising the steps of:

supporting shellfish on the bottoms of baskets and confining said shellfish in an annular space between apertured inner and outer walls of said baskets,

placing a stack of said baskets on a vertical standpipe projecting upwardly from the bottom of a tank holding water in which said baskets are submerged, said baskets being located with their inner walls surrounding said standpipe, and

causing food enriched or purified water to pass through said standpipe and out of ports spaced along said standpipe, said water being supplied at pressure sufficient to flow outwardly from the ports and radially through the baskets against the pressure of the surrounding water. 

1. A basket suitable for the culturing of shellfish, and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to allow for circulation of water, the basket further including at least three dividers extending between the said inner and outer walls, said dividers extending substantially the full height of the basket and dividing the basket into at least three segments surrounding said hole, each segment occupying less than the full width of the basket.
 1. A basket suitable for the culturing of shellfish, and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to allow for circulation of water, the basket further including at least three dividers extending between the said inner and outer walls, said dividers extending substantially the full height of the basket and dividing the basket into at least three segments surrounding said hole, each segment occupying less than the full width of the basket.
 2. A basket according to claim 1, wherein said inner hole has a diameter at least twice as large as the height of said outer wall.
 3. A basket according to claim 1 which is substantially circular, said hole being also circular and centrally located in the bottom and having a diameter at least one eighth the diameter of the basket.
 4. A basket according to claim 1, wherein said bottom and said side walls are formed integrally of plastics material by injection moulding and are of lattice construction.
 5. A basket according to claim 4, including integrally moulded means projecting upwardly above the level of the tops of said walls and shaped to engage correspondingly shaped integrally moulded registering means in the bottom of an identical basket, whereby the baskets are stackable.
 6. A basket according to claim 5, having at least three integrally moulded, circumferentially spaced, and vertically extending guide means for locating vertical suspension rope means connecting a plurality of the baskets together into a stack.
 7. A basket according to claim 1, wherein at least parts of said dividers constitute the sides of vertical grooves extending radially of said basket, said grooves being open top and bottom and extending through openings in said outer wall, whereby a plurality of said baskets may be fastened together by rope means fitted into said grooves by movement radially of the basket.
 8. A basket suitable for the culturing of shellfish, and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to allow for circulation of water, the basket further including means for locating removable dividers, said locating means comprising vertically extending recesses in the inner and outer walls.
 9. A basket according to claim 8, wherein said inner hole has a diameter at least twice as large as the height of said outer wall.
 10. A basket according to claim 8 which is substantially circular, said hole being also circular and centrally located in the bottom and having a diameter at least one eighth the diameter of the basket.
 11. A basket according to claim 8, including integrally moulded means projecting upwardly above the level of the tops of said walls and shaped to engage correspondingly shaped integrally moulded registering means in the bottom of an identical basket, whereby the baskets are stackable.
 12. A basket according to claim 11, having at least three integrally moulded circumferentially spaced, and vertically extending guide means for locating vertical suspension rope means connecting a plurality of the baskets together into a stack.
 13. A basket suitable for the culturing of shellfish, and having a bottom, an upstanding outer wall surrounding said bottom, the bottom having a hole with a diameter of at least several inches which diameter is greater than the height of said outer wall, an inner wall of substantially the same height as the outer wall surrounding said hole, said bottom and said walls being apertured to allow for circulation of water, the basket further including integrally moulded means projecting upwardly above the level of the tops of said walls and shaped to engage correspondingly shaped integrally moulded registering means in the bottom of an identical basket, whereby the baskets are stackable.
 14. A basket suitable for the culturing of oysters, having: an apertured bottom with a hole of at least several inches in diameter, an apertured upstanding outer wall surrounding said bottom and an apertured upstanding inner wall surrounding said hole, a plurality of dividers extending between said inner and outer walls, said dividers being moulded integrally with the bottom and inner and outer walls, at least parts of said dividers constituting the sides of vertical grooves extending radially of said basket, said grooves being open top and bottom and extending through openings in said outer wall, whereby a plurality of said baskets may be fastened together by rope means fitted into said grooves by movement radially of the basket, and wherein said dividers include integrally moulded spigots and recesses, the spigots and recesses being correspondingly placed and located adjacent opposite top and bottom sides of said basket, said spigots being locatable in the recesses of an identical basket whereby said baskets can be held together in register as a stack by said rope means.
 15. A basket according to claim 14, wherein said spigots and recesses are spaced inwardly of the bases of said grooves.
 16. Apparatus for feeding or purification of shellfish, by exposing the shellfish to food enriched or purified water, comprising: a tank holding water, a standpipe extending upwardly from the bottom of said tank, said standpipe having ports in its side walls and terminating in a free upper end suitable for removably receiving a shellfish basket having a hole locatable on said standpipe, means for supplying food enriched or purified water to said standpipe at a pressure such that said water will flow out of said ports when the standpipe is submerged in water in the tank, and a stack of baskets in accordance with claim 1 located on said standpipe each with its inner wall surrounding the standpipe said baskets Being immersed in said water, whereby said enriched or purified water can pass from said standpipe radially through the baskets and over shellfish held therein. 